Please review the phone no. indicated, which must contain 9-15 digits and begin with 6,8,9,71,72,73 or 74. For international numbers please indicate 00, followed by the international country code, followed by the phone number.

5-Fluorouracil (5-FU) is an antineoplastic agent widely employed in the treatment of many types of cancer.

Recent studies have proved the need for individual adjustment of 5-FU dosage based on pharmacokinetics. A simple and sensitive high-performance liquid chromatographic method for the determination of 5-FU in plasma and their preliminary clinical pharmacokinetics is described. After sample acidification with 20 microl of orthophosphoric acid (5%), the drug is extracted from plasma using n-propanol-diethyl ether (16:84).

The organic layer is evaporated to dryness, the residue dissolved in 100 microl of mobile phase and 20 microl of this mixture is injected into a LiChrospher 100RP-18 (5 microm, 250 x 4.0 mm) analytical column. Mobile phase consisted of potassium dihydrogenphosphate (0.05 M, adjusted to pH 3). The limit of quantitation was 2 ng/ml. The method showed good precision: the within-day relative standard deviation (RSD) for 5-FU (10-20,000 ng/ml) was 3.75% (2.57-5.93); the between-day RSD for 5-FU, in the previously described range, was 5.74% (4.35-7.20).

The method presented here is accurate, precise and sensitive and it has been successfully applied for 5-FU pharmacokinetic investigation and therapeutic drug monitoring.